Hyung Ham Kim

The standard-of-care for evaluating lymph node status in breast cancers and melanoma metastasis is sentinel lymph node (SLN) assessment performed with a handheld gamma probe and radioisotopes. However, this method inevitably exposes patients and physicians to radiation, and the special facilities required limit its accessibility. Here, we demonstrate a non-ionizing, cost-effective, handheld photoacoustic finder (PAF) fully integrated with a solid-state dye laser and transparent ultrasound transd

Dual-mode photoacoustic/ultrasound endoscopy (ePAUS) is a promising tool for preclinical and clinical interventions. To be clinically useful, ePAUS must deliver high-performance ultrasound imaging comparable to commercial systems and maintain high photoacoustic imaging performance at long working distances. This requires a transducer with an intact physical aperture and coaxial alignment of acoustic and optical beams within the probe, a challenging integration task. We present a high-performance

Concentric annular type dual element transducers for second harmonic imaging at 20 MHz / 40 MHz were designed and fabricated to improve spatial resolution and depth of penetration for ophthalmic imaging applications. The outer ring element was designed to transmit the 20 MHz signal and the inner circular element was designed to receive the 40 MHz second harmonic signal. Lithium niobate (LiNbO(3)), with its low dielectric constant, was used as the piezoelectric material to achieve good electrical

With global concern for climate change, and for cutting down the energy cost, especially in off grid areas, use of renewable energy has been gaining widespread attention in many areas including cellular communication. The base station (BS) has emerged as a strong candidate for the integration of renewable energy sources (RES), particularly solar and wind. The incorporation of renewable energy opens many possibilities for energy conservation through strategies such as energy cooperation between B

Single-beam acoustic tweezers (SBAT) is a widely used trapping technique to manipulate microscopic particles or cells. Recently, the characterization of a single cancer cell using high-frequency (>30 MHz) SBAT has been reported to determine its invasiveness and metastatic potential. Investigation of cell elasticity and invasiveness is based on the deformability of cells under SBAT's radiation forces, and in general, more physically deformed cells exhibit higher levels of invasiveness and therefo

Visible light communication (VLC) has recently gained significant academic and industrial attention. VLC has great potential to supplement the functioning of the upcoming radio-frequency (RF)-based 5G networks. It is best suited for home, office, and commercial indoor environments as it provides a high bandwidth and high data rate, and the visible light spectrum is free to use. This paper proposes a multi-user full-duplex VLC system using red-green-blue (RGB), and white emitting diodes (LEDs) fo

Maritime cognitive radio networks (MCRNs) have recently been proposed for opportunistic utilization of the licensed band. Spectrum sensing is one of the key issues for the successful deployment of the MCRNs. The maritime environment is unique in terms of radio wave propagation over water, surface reflection and wave occlusions. In order to deal with the challenging maritime environment, we proposed an optimal entropy-based cooperative spectrum sensing. As the results of spectrum sensing are sens